1. Field of the Invention
This invention relates generally to a novel conveyance for transporting liquids. More particularly, the invention relates to a transport container unit carried by a vehicle for transporting liquids in a manner which reduces the tendency of the liquid to surge or slosh upon acceleration (defined to be the rate of change of velocity, whether increasing or decreasing) of the vehicle when the container is only partially filled. While the invention may be used effectively on various types of vehicles, for convenience it will be discussed in connection with a motor vehicle having a need to convey a relatively small body of liquid such as a recreational vehicle and a vehicle used to convey a large amount of liquid such as a railroad tank car.
A vehicle carrying a reservoir or container partially filled with liquid is subjected to severe dynamic forces as a result of the liquid surging or sloshing within the container during movement of the vehicle. These forces are quite substantial when the vehicle is starting, stopping or making rapid changes in its velocity. Such forces are even more pronounced, when as typically is the case, the reservoir is of an elongated shape such as a tank truck with the longitudinal axis of the reservoir substantially parallel to the direction of acceleration of the vehicle. In the case of tank trucks, such surging occurs quite often when the vehicle abruptly changes speed.
The surging liquid may exert such a force against the internal walls and ends of the container as to severely damage the container or its contents. Also, when such surging does occur, the weight of the liquid is rapidly shifted to one end of the reservoir which can often result in spilling or even overturning of the entire vehicle or derailing of the tank in the case of a railroad tank car.
2. Description of the Prior Art
In the past, it has been common to provide some type of baffle means within the container in an effort to disrupt the surging flow of the liquid. These baffles have generally been used to partition the container into separate transverse compartments or units and restrict flow between these units.
One example of utilizing baffle means in a direction transverse to the surging flow is seen in U.S. Pat. No. 3,192,877 to Wright. Wright employs segments of cylindrical drums positioned across a railroad tank car to interrupt surging flow in the longitudinal direction. Another baffling system is seen in U.S. Pat. No. 3,795,204 to Waguespack. This system again attempts to position baffles across the cylindrical tank with braces positioned between the main baffles thereby obsructing longitudinal flow. Similar transverse buffer systems are seen in U.S. Pat. No. 1,832,632 to Havemeyer and U.S. Pat. No. 2,724,597 to Fowler.
One apparatus directed to transporting liquid products is the container disclosed in U.S. Pat. No. 3,023,934 to Roberts. Roberts is directed to providing a container which can be easily stored and transported by both highway trailers and water-borne means without the need of separate tank containers on each vehicle. Thus, the unit of Roberts does not address the surging problem but only attempts to provide a rigid container which is easily transferred between different types of conveyances. Roberts provides that the unit is to rest on a flat surface of the vehicle. Thus, the surging problems seen in the prior longitudinally oriented tanks also occur in the Roberts unit.
Although the prior art involves the use of baffles, such systems have consistently been positioned transverse to the expected movement of the liquid. Other containers have been provided to attempt to strengthen the structure of the reservoir and make it more adaptable to be transported by various vehicles with no provision for reducing the surging liquid flow during conveyance.